This invention relates to an information processing method and apparatus and, more particularly, to an information processing method and apparatus for displaying a list of a plurality of image data files as well as a list of search results.
The recent rapid increase in the power of computers and in the storage capacity of magnetic disks and magneto-optical (MO) disks has led to the practical use of image filing systems and image databases for storing large quantities of image data.
In these systems, images usually are stored on a computer disk in the manner exemplified by FIG. 1, which will now be described.
Shown in FIG. 1 are an image scanner 10, a personal computer 20, a display 22 and a magnetic disk 30, which is built in the personal computer 20 or externally connected to the computer.
The scanner 10 reads an image using an internal image sensor (not shown), converts the image to a digital signal and then transmits the digital signal to the personal computer 20 via e.g. an SCSI interface (not shown) and a cable 11. The image digitized by the scanner 10 is a monochrome bi-level image, an 8-bit grayscale image or a 24-bit full-color image, etc., and is capable of being selected in accordance with the input image.
The digital image read by the personal computer 20 is given a file name and then is stored on the magnetic disk 30. A plurality of items of image data that have been stored on the magnetic disk 30 are read out and displayed on the display 22 by having their file names designated by the operator of the personal computer.
However, an image filing system of this kind has the following problems:
First, since the quantity of image data is very large, reading the designated image data out of the disk and displaying the image data take time. For example, in case of a 400-dpi monochrome bi-level image of size A4, the amount of data is approximately two megabytes. If the image is a full-color image, the amount of data is about 48 megabytes. As a consequence, a considerable period of time is required even to transmit the monochrome image via the interface (e.g. the SCSI and cable 21) between the personal computer and the disk. In case of the full-color image, the time required is much greater.
In general, image compression is carried out to solve this problem. For example, the JPEG compression method is used widely to compress full-color images. In accordance with the JPEG method, it is possible to compress image data to {fraction (1/20)} to {fraction (1/30)} of the original without much deterioration in image quality. However, even though the time for transmitting data from the disk to the personal computer is shortened when compression is carried out, processing for decoding the compressed image data by the personal computer is necessary. This means that considerable time is still required.
Second, in order to find a desired image among stored images (this is referred to as a manual search) or to verify the image, an enormous quantity of compressed image data must be read out of the disk, decoded and then displayed each time.
Further, the display 22 usually has a resolution which is low in comparison with that of the image data that has been stored on the disk 30. When an image is displayed, therefore, processing such as subsampling is required. Accordingly, in a situation where a stored image is manually searched or verified, it is required that each image file be displayed one at a time. This is extremely inefficient.
In order to improve upon these drawbacks, a filing system which performs a search using reduced images referred to as thumbnail images has been proposed. Such an example is illustrated in FIG. 2.
Numerals 20, 22 in FIG. 2 represent the personal computer 20 and display 22 shown in FIG. 1.
A reduced image (thumbnail image) is produced for each image file in advance and the thumbnail image is displayed instead of the stored image having the original dimensions. Since a thumbnail image has a smaller data size than the image of the original size, it is transmitted from the disk in a shorter period of time. An additional advantage is that a multiplicity of thumbnail images 23, 24, 25 can be displayed on the display 22 at one time.
Nevertheless, a system of this kind still has a number of disadvantages.
Specifically, since a thumbnail image per se is merely for the purpose of displaying the general features of the full-size image, it is desired that the thumbnail image be in the same file as that of the image of the full-size image. However, if a thumbnail image and the full-size image are included in one file, the file must have a special format and it will not be possible to read the file out of another application or from a filing system. In addition, if the number of stored images is large, problems arise in terms of the amount of data possessed by the thumbnail images.
On the other hand, if a thumbnail image and its full-size image are placed in separate files, management becomes more complicated.
In a case where a thumbnail image and its full-size image are placed in separate files, an application which manages filing must manage the correlation between the thumbnail image and full-size image. Consequently, when the user executes processing such as movement, copying, renaming or deletion of a file by the function of the operating system (OS) or by an application belonging to the OS, a contradiction occurs with respect to correlation with the filing application.
Another drawback is that a thumbnail image is produced arbitrarily as a file irrespective of the volition of the user. Furthermore, if the number of stored images is large, problems arise in terms of the amount of data possessed by the thumbnail images.
In order to prevent the occurrence of the above-mentioned contradiction in terms of the correlation between a full-size image file and its thumbnail image file, a filing system having a database structure has been proposed. With this database structure, there are many cases where a plurality of retrieved files are displayed as thumbnail images by performing a search among a number of image files using a keyword search or the like. In a database structure of this kind, image files are managed within the database structure and the file management structure is invisible to the user. For example, since the user cannot see the directory structure directly, a file which could not be retrieved as by a keyword search can only be retrieved by displaying files one after another. This is inconvenient. Further, even in a case where files having a directory structure are provided on a separate medium such as a CD-ROM, all images must be moved to a database area and a change must be made to a structure to which the thumbnail images have been added.
Thus, in the image filing system described above, the following drawbacks are encountered in a case where a manual search is performed to select a desired image from a plurality of images:
1. A long period of time is required to display image for the sake of verifying an image.
2. With an image search using thumbnail images, a special type of management is needed to manage the thumbnail images and full-size images and difficulties arise when processing the images from the OS or another application.
3. When there is a large number of filed images, problems arise in terms of the volume of data of the thumbnail images.
4. In an image filing system having a database structure, the structure cannot be seen by the user. As a result, inconveniences arise in a case where a desired image is retrieved while displaying and verifying images.
5. In an image filing system having a database sturcture, it is not possible for the user to manage image files disposed under a desired directory.
6. In order to perform an image search of another image file area having a directory structure, a change must be made to a database structure. Operation is complicated and processing takes too much time.
Accordingly, an object of the present invention is to provide an information processing method and apparatus in a file system having a hierarchical tree structure based upon directories, wherein it is possible to display thumbnail images of image data files in accordance with the tree structure.
By making it possible to present such an image data file display, the user can retrieve a desired image from a plurality of images simply and at high speed.
Another object of the present invention is to indicate image data files present in one directory by thumbnail images and, with regard to another directory which belongs to the first-mentioned directory, to indicate one image data file present in this other directory by a thumbnail image, thereby making it possible to readily ascertain whether an image data file is present in the other directory.
In accordance with an embodiment of the present invention, there is provided an information processing method for managing image data files by a file system having a hierarchical tree structure in which directories and files are placed under another directory, comprising a first generating step of generating a thumbnail image on the basis of each image data file that belongs to a desired directory, a first display step of displaying the thumbnail images generated at the first generating step, a second generating step of generating a thumbnail image on the basis of one image data file among image data files that belong to another directory belonging to the desired directory, and a second display step of displaying the thumbnail image generated at the second generating step.
In accordance with another embodiment of the present invention, there is provided an information processing apparatus for managing image data files by a file system having a hierarchical tree structure in which directories and files are placed under another directory, comprising first generating means for generating a thumbnail image on the basis of each image data file that belongs to a desired directory, first display means for displaying the thumbnail images generated by the first generating means, second generating means for generating a thumbnail image on the basis of one image data file among image data files that belong to another directory belonging to the desired directory, and second display means for displaying the thumbnail image generated by the second generating means.
A further object of the present invention is to decode, over a plurality of stages, coded image data capable of being decoded at multiple levels, whereby it is possible to discover, at a low-level decoding stage, whether an image is a desired image, thereby raising the efficiency of image retrieval.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.